Here are the surveys that help deliver potential customers for companies:

Curved Air Marketing Solutions Limited, is a market research company based in Blackburn. It claims it get 20,000 people a week to complete one of its telephone marketing surveys.

Around 800 trueCall users were called 1,176 times by the firm during the last year. If the pattern were repeated across Britain this would represent 3.7 million calls to home phones a year from the firm. The company began trading two years ago and is yet to post a profit.

It is run by William Taylor, a Northwich-based businessman who is also the chairman of a finance company, a Blackburn roofing firm and was previously a director of a series of kitchen design businesses.

According to Curved Air’s website it creates a “database of potential customers that continually grows leads for you, our client” through the people it calls completing 20,000 surveys a week. The company did not respond to requests for comment.

National Energy Services Limited, based in Swansea, telephoned 339 members of trueCall panel 2,135 times in the last 12 months. This would represent 1.6 million calls to British homes during the year.

According to its website, the firm is the “UK’s largest provider of energy efficiency surveys” and, it says, is “dedicated to helping home-owners and businesses claim the government grants available to make energy efficient upgrades to their properties”.

The firm had a turnover of £16 million last year and is part of the Save Britain Money group run by Neville Wilshire, who runs a series of other firms including Fuelswitch.co.uk and Debts Reduced Limited.

The company has gone from six to 600 employees in four years, expanded to have a call centre in Cardiff which was opened by Craig Bellamy, the footballer, and is to feature in a fly-on-the-wall documentary on BBC3 later this year.

A spokesman for the firm said: “To help people access the funding available we call potential customers in their homes from our UK contact centre. At NES we have strict processes and procedures. Our technology is Ofcom compliant. Even with all the technology that is available and our very successful quality control methods; it is inevitable that a small percentage of people contacted will not be fully satisfied with the call.”

Ismart Consumer Solutions calls were intercepted 1,284 times by 483 trueCall machines in our survey, representing 2.2 million calls a year across the country.

It claims that “customers find us through carefully selected partnerships” or “ purely through word of mouth” but in fact makes large numbers of “cold” calls to canvas for business.

Founded by David Haycock, 33, Ryan Horne, 32, and Dylan Pritchett, 33, its most recent accounts show it had a turnover of £6.5million, and paid the three directors £515,000 in salaries and shares.

Last year it was accused of demanding huge fees for its help with one customer who was reportedly awarded £2,365 compensation ending up getting nothing and receiving a £890 bill for commission from the firm.

Paul Fakley, its marketing director, said: “We take great pride in the fact that many of the calls we make ultimately result in significant financial benefits to consumers who make claims through us. Without our marketing activity many consumers would likely miss out on the opportunity to get back what is rightfully theirs. We abide by all Ofcom regulations that apply to us.”